Electric cable system



Jan. 9, 1940. c. E. BENNETT 2,135,445

ELECTRIC CABLE SYSTEM Original Filed April 16, 1934 INVENTOR NEYS.

Patented Jan. 9, 1940 PATENT OFFICE ELECTRIC CABLE SYSTEM Charles E. Bennett, Ridgewood, N. 1., assignor to The Okonite-Callender Cable Company, In-

corporated, Paterson New Jersey N. 1., a corporation oi Original application April 16, 1934, Serial No. 720,734. Divided and this application Februan 19, 1937, Serial No. 126,615

3 Claims.

This invention is directed to an improvement in underground high tension electric cables of the type disclosed in Patent No. 2,015,063, dated September 24, 1935.

The present application is a division ,of my copending application Serial No."720,734, filed April 16, 1934.

In the patent above referred to I have disclosed a cable system comprising an oil-filled pipe line buried in the earth and containing insulated but unsheathed cable conductors, the pipe line being of sufliciently large internal diameter to permit of drawing in of the unsheathed insulated conductors and to permit free relative movement of the conductors within the pipe line to permit the conductors to "snake". The pipe line is fllled with an insulating fluid maintained under sumciently high pressure to increase its dielectric strength, pressures, for example, from five atmospheres upward.

While such a construction provides improved heat dissipating characteristics as compared with prior cable systems, the invention constituting the subject matter of the present divisional application provides additional cooling means and minimizes the chances of hot spot" formation due to inequalities of heat dissipation in the earth.

Generally speaking the present invention provides a construction in cable systems of the type briefly referred to above wherein the oil or other insulating fluid is caused to surge in the pipe line, first in one direction and then the other, the oil in its surging movement passing through cooling means.

In the drawing accompanying this application I have shown an embodiment of my invention in elevation.

Referring to the drawing in detail, i designates a pipe line in which the cable conductors, which are insulated with paper or other suitable impregnated insulation but unsheathed, are enclosed. The pipe line is provided at suitable intervals with joints 2. By-passing each joint and at any other locations in the line that may be found suitable or desirable are by-pass pipes 3. These pipes are equipped with radiators I. If desired the joints 2 may be provided with baiile plates to retard movement of the insulating o fluid in the pipe line I and increase the movement of this insulating fluid through the by-pass pipes 3 and radiators 4.

The pipe line I, as will be understood, is filled with oil or other insulating fluid in which the 55 insulated but unsheathed conductors are immersed, this fluid being maintained at a willciently high pressure to increase its dielectric strength say, for example, five atmospheres minimum.

Adjacent one end of the pipe line i I provide a pump I which is driven by electric motor I and which builds up and maintains the desired pressure on the insulating fluid within the pipe line I.

The intake side of the pump is connected to a reservoir 9 by pipe line 9. This reservoir is conveniently equipped with suitable switches III and H for'automatically controlling the operation of the pump motor I.

A relief valve I! in series with a solenoid valve I3 is provided across the intake 9 and discharge pipe H of the pump.

At a point remote from the reservoir; 8 I provide an accumulator shown diagrammatically at It, this accumulator being connected to the pipe line I by a pipe It. The by-pass pipes 3 and radiators 4 are intermediate the reservoir 8 and accumulator l5.

With this system in operation it will be appreciated that insulating fluid will be pumped from the reservoir 8 through the pipe 9, pump 8, discharge pipe l4 and the cable pipe line I, by-'- pass pipes 3 and radiators I to the accumulator ll. As this fluid is supplied to'the accumulator, the latter will expand, as will be understood, so that when the oil in the reservoir 8 has reached a predetermined level, dependinglupon the set-" ting of the switch II, the pump 6 will automatically shut off. Thesolenoid valve It will open and the accumulator II will .then force the fluid back to the reservoir 8 through the by-pass pipes I, radiators l, solenoid valve it until the level of the fluid in the reservoir 8 operates the float switch Ill again to close the solenoid to the pump 8 to begin another cycle of operation.

The solenoid valve llcloses when the motor 1 is started and opens when the motor is stopped, thus allowing the fluid to flow from the pump 9 to the accumulator l5 and back again to the reservoir l. The relief valve i2 is set ata lower pressure than that given by the accumulator II in order that there will be an excess of pressure to force the insulating fluid through the pipe line and cooling system back to the reservoir.

As-above mentioned, when the motor 1 starts the solenoid valve it closes and the insulating fluid is pushed into the accumulator ll so that at this stage the accumulator governs the pressure. When the motor 1 stops the solenoid valve It opens allowing the relief valve I! to function so that the relief valve governs the minimum valve but it is to be understood that other types of automatic valve may be employed if desired.

The capacity of the accumulator I5 is suii'iclent to take care of the fluid contained in the length of pipe line I between adjacent joints 2 so that I am assured of maximum cooling in that the entire mass of fluid in the pipe line is necessarily moved through the radiators 4. If desired the accumulator. It may be substituted by a gas reservoir capable of building up a pressure as fluid is forced thereinto by the motor driven pump i.

It will be apparent that the above described construction provides for a surging back and forth of all of the insulating fluid in the pipe line I, this fluid in its movements passing through the radiators l. i

It is to be understood that I have shown a pump at one end of the system and an accumulator at the other merely for purposes of illustration and description, inasmuch as, obviously,

pumps and acumulators may be distributed along the system at any desired point.

It is to be understood that changes may be made in the details of construction and arrangement of parts above described within the purview of this invention.

What I claim is:

1. In combination, an oil filled cable, heat radiating means disposed at intervals along the exterior of the cable and communicating with the interior thereof, a pump at one side of the heat radiating means, and an accumulator at the opposite side, said pump and accumulator operating alternately thereby to efl'ect movement of the oil in the cable through the heat radiating means, flrst in one direction and then in the opposite direction, the total cross section of the oil at any instant moving in the one direction.

pressure and the rate of flow from the accumu- 2. In combination, an oil filled cable, heat radiating means disposed at intervals along the exterior of the cable and communicating with the interior thereof, a pump at one side of the heat radiating means and having its discharge side connected to the cable, a motor for driving said pump, a reservoir connected -to the intake side of said pump, switch mechanism for controlling the circuit. of said motor, said switch mechanism being controlled by the level of the oil in said reservoir, and an accumulator at the side of the heat radiating means, opposite to the said pump, cooperating with said pump, the pump eI-' fecting movement of the oil in the cable through said heat radiating means in one direction, the accumulator eflecting movemeht of the oil in the cable in the opposite directio the total cross section of the oil at any instant moving in the one direction.

3. In combination, an oil filled cable, heat radiating means disposed at intervals along the exterior of the cable and communicating with the interior thereof, a pump at one side of the heat radiating means having its discharge side connected to the cable, a reservoir connected to the intake side of said pump, a relief valve and a solenoid valve connected in series across the intake and discharge of said pump, float switches in said reservoir for starting and stopping said pump automatically and in accordance with the level of the oil in said reservoir, and an accumulator at the side of the heat radiating means opposite to the pump connected to said cable, said pump and accumulator cooperating to effect movement of the oil in the cable, first in one direction and then in the opposite direction through said heat radiating means, the total cross section of the oil at any instant moving in the one direction.

CHARLES E. BENNETT. 

